In your other post about the Model Mangaer, both Axel and I said not to use it, so the "best practice" is not to use it at all, put your content model in an SDK based project, build an AMP, and deploy the same AMP to both nodes.

However, if you ignore this advice and use the Model Manager, it will work across your cluster because the model is checked in to the repo just like any other piece of content.